Pair correlations in the attractive Hubbard model

The mechanism of fermionic pairing is the key to understanding various phenomena such as high-temperature superconductivity and the pseudogap phase in cuprate materials. We study the pair correlations in the attractive Hubbard model using ultracold fermions in a two-dimensional optical lattice. By c...

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Bibliographic Details
Main Authors: C. F. Chan, M. Gall, N. Wurz, M. Köhl
Format: Article
Language:English
Published: American Physical Society 2020-05-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.2.023210
Description
Summary:The mechanism of fermionic pairing is the key to understanding various phenomena such as high-temperature superconductivity and the pseudogap phase in cuprate materials. We study the pair correlations in the attractive Hubbard model using ultracold fermions in a two-dimensional optical lattice. By combining the fluctuation-dissipation theorem and the compressibility equation of state, we extract the interacting pair-correlation functions and deduce a characteristic length scale of pairs as a function of interaction and density filling. At sufficiently low filling and weak onsite interaction, we observe that the pair correlations extend over a few lattice sites even at temperatures above the superfluid transition temperature.
ISSN:2643-1564